FIFE::Instance should inherit blocking property from FIFE::Model

Description

Currently FIFE::Model stores a blocking property. The pathfinder uses this property to determine if a cell contains blocking instances. Unfortunately this produces a problem when you have multiple instances using the same model. All instances using that model will be blocking causing unwanted behavior if there a any exceptions.

The solution to this would be to add a blocking property to FIFE::Instance and have it inherit the blocking property value from Model. This allows a default blocking value to be applied to all instances using a model AND allow it to be overridden by the client if the need arises. The pathfinder would query the blocking property of the instance and not the model and continue to work as it is now.

As part of this ticket the implementer should also add the ability to set an instances blocking property (overriding the model blocking property value) with the editor and store that value in the map file format. Also update the map format document on the Wiki.

(In [3517]) * Instances now inherit blocking property from objects. Modified the ObjectEdit? Plugin, so you can use it to change the object blocking or the Instance blocking individually. Note: Object blocking changes, overwrite the instance blocking property. closes #514